In a signal transmission line having an inductance value L and a capacitance value C, a transmission delay time T.sub.p is generally defined by: EQU T.sub.p =.sqroot.L.times.C.
The characteristic impedance I.sub.c thereof is defined by: ##EQU1##
Where a time adjustment of a pulse signal is necessary by delaying the timing of the pulse signal by a predetermined value, it is known to use a delay line device having a suitable inductance L and a distributed capacitance C calculated from the above relation. When a circuit arrangement made by merely connecting an inductance element to distributed capacitors is used, the circuit arrangement acts as a resonance circuit and the wave form of the signal transmitted through the circuit is distorted. To avoid this, a cascade circuit having a plurality of inductance elements and a plurality of distributed capacitors connected in a cascade manner is used to suppress the resonance effect.
A delay line of a distributed parameter circuit type is an ultimate form of the circuit arrangement adopting the idea of the above-mentioned technique.
When dealing with relatively slow signals, e.g., the rise time and the fall time of the signals are relatively long, a conventional delay line of the cascade type formed by a plurality of discrete inductive elements and a plurality of distributed capacitors is a practical delay line system. However, when dealing with relatively high speed pulse signals having a rise time or fall time shorter than a nano second, delay lines having nearly the ideal distributed parameter elements for controlling the delay time of a high speed pulse signal are desired. In addition, it is desired to provide delay line systems with a smaller size and a higher accuracy.